Glioblastoma (GBM)

What is glioblastoma (GBM)?

Glioblastoma (GBM) is the most common type of malignant (cancerous) brain tumor that starts in the brain in adults. Cancer cells in glioblastoma tumors rapidly grow and multiply. The cancer can spread into other areas of your brain and spinal cord as well. Rarely, the cancer spreads outside your brain to other parts of your body.

Glioma tumors like GBM start in glial cells. Glial cells are vital to nerve cell function. Glioblastoma specifically forms in glial cells called astrocytes. GBMs are the fastest-growing astrocytoma (a tumor that forms in astrocytes).

Glioblastoma, formerly known as glioblastoma multiforme, is a devastating type of cancer that can result in death in fewer than six months without treatment. It’s important to seek diagnosis and treatment as soon as possible to prolong your life.

How common is glioblastoma?

More than 13,000 Americans are diagnosed with GBM every year. Glioblastoma accounts for almost half of all cancerous brain tumors.

What are the symptoms of glioblastoma?

Glioblastoma symptoms tend to come on quickly. The growing tumor puts pressure on your brain and can destroy otherwise healthy brain tissue, causing:

• Blurred or double vision.
• Headaches.
• Loss of appetite.
• Memory problems.
• Mood or personality changes.
• Muscle weakness or balance issues.
• Nausea and vomiting.
• Seizures.
• Speech problems.
• Changes in sensation, numbness or tingling.

What causes glioblastoma?

Like other gliomas (tumors that form in your brain and spinal cord), research suggests that changes in your DNA lead to the development of glioblastoma brain tumors. Your genes contain DNA. They give instructions to your cells about how to grow and multiply. Mutations, or changes, to the DNA in your genes can cause cells to multiply out of control.

Is glioblastoma hereditary?

Research suggests that it’s possible to inherit genetic variations from your biological parents, but inherited GBMs are rare. Most commonly, these mutations happen randomly during your lifetime.

What are the risk factors for glioblastoma?

Glioblastoma most commonly affects people ages 45 to 70. The average age at diagnosis is 64. Men and people assigned male at birth (AMAB) have a slightly higher risk, but the disease affects all ages and sexes.

These factors may increase your risk:

• Exposure to chemicals, like pesticides, petroleum, synthetic rubber and vinyl chloride.
• Genetic, tumor-causing conditions, like neurofibromatosis, Li-Fraumeni syndrome and Turcot syndrome.
• Previous radiation therapy to your head.

What are the complications of glioblastoma?

Glioblastoma and its treatments can affect brain function. You may experience mood changes and memory problems. Most people with GBM eventually have to stop working and driving. You may need full-time care. These changes may lead to anxiety disorders or depression.

How is glioblastoma diagnosed?

A healthcare provider will evaluate your symptoms and perform a neurological exam. If they suspect you may have a brain tumor, you may have these tests:

• MRI or CT scan to look for brain tumors.
• Biopsy to obtain a sample from a tumor and examine the tissue for cancer cells.

What are the grades of glioblastoma?

Healthcare providers use a grading system from I (1) to IV (4) to indicate brain tumor behavior. Grade I brain tumors grow slowly and are the least aggressive. Grade IV tumors grow rapidly and are more aggressive.

Glioblastoma tumors are grade IV by definition. Glioblastoma can be either primary or secondary. Primary GBM develops directly from glial cells. On the contrary, occasionally, grade I glial tumors can progress to become GBMs — this is called secondary GBM.

How is glioblastoma managed or treated?

Unfortunately, there isn’t a cure for glioblastoma. Treatments focus on removing or shrinking the tumor to reduce symptoms, extend your life and improve the quality of your life.

The first step is surgery to remove the tumor (craniotomy), followed by radiation and chemotherapy. If surgery isn’t an option due to your health or the tumor location, your cancer care team may suggest radiation and chemotherapy to try to manage the tumor.

Glioblastoma treatment includes:

• Radiation therapy: Radiation therapy uses X-rays to damage cancer cells so they can’t grow. You may need as many as 30 daily radiation treatments over six weeks.
• Intensity-modulated radiation therapy (IMRT): IMRT allows the delivery of radiation to the tumor while minimizing the radiation dose to the surrounding healthy brain tissue.
• Stereotactic radiosurgery: Gamma knife radiosurgery is a type of advanced radiation therapy. (Despite the name, it’s not a surgical procedure.) Highly focused energy beams precisely target the tumor, limiting damage to healthy tissue. Providers occasionally use this technique when GBM grows after receiving initial IMRT.
• Chemotherapy: Chemotherapy medication circulates in your blood to kill cancer cells. You may receive chemotherapy at the same time as radiation therapy as well as after radiation therapy is completed.
• Laser interstitial thermal therapy (laser ablation): This is a minimally invasive procedure that uses laser energy to destroy the tumor.
• Targeted therapy: Instead of chemotherapy, you may receive targeted therapy. This treatment targets certain cell changes that fuel cancer growth.
• Tumor treatment fields (TTF): A wearable device sends low-intensity electric fields (TTFs) to the tumor through electrodes on your scalp. TTFs disrupt cancer cells, preventing them from multiplying and growing. Providers may consider this treatment after chemo-radiation is complete.
• Immunotherapy: This therapy uses your body’s immune system to fight the GBM cells.
• Palliative care: Palliative care provides symptom relief, comfort and support to people living with serious illnesses like cancer.

How can you prevent glioblastoma?

Unfortunately, genetic mutations cause glioblastoma and they aren’t preventable. But early detection and treatment may slow the progression of a tumor.

If brain tumors run in your biological family, you may want to consider genetic testing. Talk to a healthcare provider or a genetic counselor about the risks and benefits of genetic testing.

What is the prognosis (outlook) for people who have glioblastoma?

Glioblastoma is an aggressive cancer that’s difficult to treat. There isn’t a reliable cure. Treatments ease symptoms. They help you stay comfortable and prolong your life. There are many clinical trials underway to find new GBM treatments. On rare occasions, a GBM patient may be cured with aggressive treatment, but aggressive treatment rarely results in a cure.

Therapies that target specific cancer cell genes show promise. Researchers are also looking at ways to deliver chemotherapy directly to the brain tumor. Your healthcare provider can determine whether a clinical trial is right for you.

Unfortunately, most people live an average 12 to 18 months after diagnosis. The five-year survival rate for glioblastoma is only about 5%. That means about 5% of people with GBM are still alive five years after their diagnosis.

When should I see my healthcare provider?

You should call your healthcare provider if you experience:

• Memory problems.
• Seizures.
• Severe headaches or vision issues.
• Unexplained weight loss or nausea and vomiting.
• Change in personality.
• Progressively worsening weakness, numbness or speech problems.

What questions should I ask my healthcare provider?

You may want to ask your healthcare provider:

• Why did I get glioblastoma?
• What’s the best treatment for me?
• What are the treatment risks and side effects?
• What type of follow-up care do I need after treatment?
• Should I look out for signs of complications?
• Should I or my family have genetic testing done?